Alcohol dependence (AD) is a chronic and relapsing condition affecting 10 million Americans. To date, only four pharmacotherapies are approved by the FDA for the treatment of alcoholism and their efficacy is modest. Therefore, medication development for AD represents a high priority area. Ibudilast (IBUD) is a glial cell modulator that inhibits phosphodiesterases (PDE) -4 and -10 and macrophage migration inhibitory factor (MIF). Preclinical data suggest that neuroimmune modulation is critical to the rewarding properties of drugs of abuse, including alcohol. Further, IBUD has been shown to enhance GDNF release in vivo and GDNF modulation has been implicated in alcohol reinstatement in animals, while PDE inhibition has been shown to reduce alcohol intake in mice. Together, these findings suggest that neuroimmune modulation constitutes a novel target for the treatment of alcoholism. The objective of this Developmental/Exploratory (R21) application is to advance medication development for alcoholism by conducting an initial Phase II study of IBUD for AD. Consistent with our ongoing program of research, human laboratory models are proposed to obtain initial efficacy data and to translate promising preclinical findings. Specifically, the proposed study consists of a randomized, double- blind, placebo-controlled within-subject crossover design to determine the safety, tolerability, and initial human laboratory efficacy of IBUD in a sample of 24 non-treatment seeking individuals with either alcohol abuse or dependence treated with IBUD (50mg BID) and placebo. Participants will complete two separate 7-day inpatient stays at the UCLA CTRC during which they will take the study medication, complete an IV alcohol challenge, and take part in a stress-exposure and cue-exposure paradigms. Specific aims are to test whether IBUD (a) is safe in the context of alcohol administration, (b) attenuates alcohol-induced reinforcement, and (c) dampens stress-induced and cue-induced alcohol craving. In sum, this study will efficiently evaluate safety and initial efficacy of IBUD thereby screening novel medications for AD and elucidating potential mechanisms by which IBUD may be clinically efficacious. Results from this study will inform a subsequent R01 application to conduct a randomized controlled trial of IBUD for alcoholism.